Dust guard for circular saws

ABSTRACT

An improved design for a dust shroud providing an airflow conduit for collecting dust off a work piece and a saw blade is disclosed. The dust shroud is configured with either one or two extending and telescoping lower rigid jaws that are durable and can engage a work piece at different angles. A novel roller is additionally provided for moving along a work piece.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/179,260, filed Feb. 12, 2014, entitled “DUST GUARD FOR CIRCULARSAWS,” which claims priority to and the benefit of U.S. ProvisionalPatent Application Ser. No. 61/763,778, filed Feb. 12, 2013, which isentitled “DUST GUARD FOR CIRCULAR SAWS”. Accordingly, the entirecontents of each of the aforementioned patent applications are herebyexpressly incorporated by reference.

TECHNICAL FIELD

The present invention pertains generally to masonry and carpentry saws.Particularly, the present invention relates to cutting tool devices andmethods to maximize containment of dust while cutting cinder block,concrete, brick, clay, stone, tile, wood, and the like. Morespecifically, the invention pertains to a dust guard configured to acircular saw setting up a conduit for suctioning dust.

BACKGROUND

Devices for grinding or cutting masonry or stone materials have beenknown for some time. Also known, is a problem of uncontrolled release ofand exposure to airborne dust and particulate matter as a by-productfrom the grinding and cutting. As a result, government agencies such asOSHA have promulgated safety and health requirements for wet and drycutting. In addition to health issues, the dust by-products present aclean-up challenge, even if all individuals in a contained environmenthave donned respirators.

Many prior art solutions have been proposed that specifically employ drymeans to control dust. Still other examples specifically provide a dustshroud (or dust guard) configured to a saw blade and forming a conduitfor collecting dust off a work piece. One such example was proposed byLoveless et al. entitled “Dust Shroud for Gas Powered Circular Saws,”U.S. Pat. No. 8,011,398, and assigned to Dustless Depot, LLC. In thisdesign, the dust shroud is configured to a leading edge of the circularsaw blade. Also, the frontal shroud forms a conduit that leads dust awayfrom a front of the saw. However, this configuration seems less thanideal. For example, a separate vacuum apparatus is needed with a vacuumhose, mobility and portability are restricted.

Still another related dust shroud was patented by Loveless also assignedto Dustless Depot, LLC, entitled “Universal Dust Collection Shroud forHigh Speed Gas Powered Saws,” U.S. Pat. No. 8,381,711. In this example,a side exhaust port is coupled to a power saw shroud. Some drawbacks,however, are that the geometry is very asymmetrical and awkward; and itwill not retract across a work piece, thereby providing less suction todust coming off a work piece that can be achieved.

Yet another similar dust shroud was disclosed by present inventor, Guthentitled “Power Saw Apparatus with Integrated Dust Collector,” U.S. Pub.Pat. App. No. 20111 0079207. This earlier design comprises a flexiblebellows (dust guard) framed by a rigid upper shroud (FIG. 1). While thedesign is a major improvement over previous dust collection devices andmethods, there may still remain some drawbacks to that particularsolution. Initially, the flexible bellows is relatively difficult tomanufacture. Also, the flexible design is prone to deform and may beforced into the blades further damaging the bellows. The dust guardherein seeks to proved strength and longevity to the device.

In light of the above, it is an object of the present invention toprovide a dust guard for circular saws that provides added durability tothat particular component. It is an additional object of the presentinvention to provide lower jaw having a leading edge that may beconfigured with attachments for cutting at different angles.

SUMMARY

The present invention specifically addresses and alleviates the abovementioned deficiencies associated with the prior art. More particularly,the present invention in a first aspect, is dust guard for providing anair flow conduit at a saw blade comprising: an upper shroud surroundingan upper portion of the saw blade providing an air flow conduit as wellas housing and providing safety to a saw user; a lower shroudsurrounding a rear lower portion of the saw blade the lower shroudcomprising a rear exit for dust and air flow; a telescoping jaw rotatingabout a pivot point with respect to the upper and lower shroud; and aspring coupling the telescoping jaw to the upper shroud configured suchthat a spring force holds the telescoping jaw fully extended in an openposition, wherein further a fully retracted position comprises a forceopposite spring force.

The invention in this aspect is additionally characterized in that thedust guard may have a telescoping jaw with one or two telescopingportions (i.e. a middle jaw telescoping with respect to the lowershroud; and a forward jaw telescoping with respect to the middle jaw).Additionally further, the forward jaw comprises: a roller at ahorizontal leading edge of said forward jaw; and a first scoop having afirst angled surface removably secured with respect to the forward jaw,the first scoop providing a guide for making angled cuts; and a secondscoop removably secured with respect to the forward jaw andinterchangeable with respect to the first scoop, the second scoopproviding a second angled surface with respect to the first scoop angledsurface.

The dust guard in this aspect in additionally characterized ascomprising: a tab at a rear end of the middle jaw; a ridge wall at ajunction between the upper shroud and the lower shroud, the ridge wallproviding a rear stop against the tab when the middle jaw is fullyretracted; and a bump stop coupled to the lower dust shroud, the bumpstop contacting the tab and providing a forward stop when the middle jawis fully extended.

The dust guard for providing an air flow conduit at a saw blade in thisaspect is additionally characterized as further comprising a flangeconfigured between the upper shroud and the lower shroud, the flangeconcentric to the saw blade. Also, the invention is further definedwherein the spring comprises a helical torsion spring and is configuredabout the pivot point, and wherein further the spring comprises an armcoupled to a horizontal shoulder screw, the horizontal screw coupled tothe telescoping jaw. Further, the horizontal screw is configured thougha slot in the upper shroud wherein the horizontal screw slides along aslot length as the telescoping jaw rotates with respect to the uppershroud.

The slot herein is additionally characterized as a first slot, whereinthe telescoping jaw further comprises a forward jaw and a middle jaw,the middle jaw further comprising an inner slot configured within thefirst slot and having a shorter length, wherein when the horizontalscrew travels the length of the inner slot, the horizontal screwcontacts an end of said inner slot and further moves the middle jaw aremaining distance along the first slot as the forward jaw and middlejaw fully retract and extend.

The invention can be better visualized by turning now to the followingdrawings wherein like elements are referenced by like numerals.

These, as well as other advantages of the present invention will be moreapparent from the following description and drawings. It is understoodthat changes in the specific structure shown and described may be madewithin the scope of the claims, without departing from the spirit of theinvention.

While the apparatus and method has or will be described for the sake ofgrammatical fluidity with functional explanations, it is to be expresslyunderstood that the claims, unless expressly formulated under 35 USC112, are not to be construed as necessarily limited in any way by theconstruction of “means” or “steps” limitations, but are to be accordedthe full scope of the meaning and equivalents of the definition providedby the claims under the judicial doctrine of equivalents, and in thecase where the claims are expressly formulated under 35 USC 112 are tobe accorded full statutory equivalents under 35 USC 112. The inventioncan be better visualized by turning now to the following drawingswherein like elements are referenced by like numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself,both as to its structure and its operation, will be best understood fromthe accompanying drawings, taken in conjunction with the accompanyingdescription, in which similar reference characters refer to similarparts, and in which:

FIG. 1 is a prior art blade guard device with a flexible retractablebellows configured as a lower jaw to the blade guard device;

FIG. 2 is a first profile view of the present invention;

FIG. 3 is a perspective view of the dust guard for circular saws;

FIG. 4 is a top plan view thereof;

FIG. 5 is a front view of the embodiment;

FIG. 6 is an additional enlarged profile view of the present invention;

FIG. 7 is an exploded view thereof showing all components;

FIG. 8 is an enlarged view of components circumscribed by line 8 in FIG.1; and

FIG. 9 and FIG. 10 are additional profile views illustrating how thelower jaws of the present invention retract.

DETAILED DESCRIPTION

Referring initially to the FIG. 2 and FIG. 3, a first improved bladeguard 10 (coupled to saw 90) is illustrated having a shroud 20 withupper 21 and lower 22 portions generally protecting an upper and rearlower blade 91. The shroud 20 upper and lower portions are one piecewith the lower portion being wider to accommodate retracting andtelescoping lower jaws 31, 41 as further detailed herein. Thetelescoping lower jaws 31, 41 together provide an enclosure about alower blade 91, and importantly provide a dust conduit capable ofholding a negative pressure with respect to atmosphere therein. Also asdetailed herein, the lower jaws 31, 41 rotate about an axis (pivot) 53slightly above and inward of the circular saw 91 axis 92. Also, acircular flange 24 at the shroud portion 20 configured to one side orthe other for coupling to a fixed portion of the saw 90 via apertures 25having extra material carved out thereof to accommodate a screw or boltfastener head. A spring housing 26 further protrudes outwardly from theupper shroud 21 provided to contain a spring 51, wherein torsion springforce maintains lower jaws 31, 41 fully extended. Telescoping herein isessentially defined as forcing into one another in the manner of slidingtubes of a telescope. As claimed herein, the telescoping jaw 31,41comprises forward jaw 41 and middle jaw 31 telescoping with respect tolower shroud 21.

With regard to FIG. 4, a top plan view is provided for the dust guard10. Here it is revealed that the spring housing protrudes from eitherside of the device 10; and hence, the jaws 31, 41 move against thespring 51 force. However, the invention 10 would still function withonly one spring 51 to either side. At a rear portion of the lower shroud22, a conduit 29 is formed where dust would exit rearwardly to a filterchamber and a dust holding area. At a forward end of the dust guard 10and at a leading edge of the forward jaw 41, a roller is configuredthereto to roll along a work piece while cuts are being made thereto.Also configured to said leading edge and around the roller, a scoop 63is removably configured thereto for guiding specific angle cuts to awork piece via angled slope 63 a. With regard to FIG. 5, a front view ofthe present invention 10 is provided. Herein, alternative views areprovided showing the forward jaw 41 having a roller 61 and a scoop 63configured thereto.

FIG. 6 provides an additional enlarged profile view of the inventionembodiment 10. As shown, a slot 27 is provided in the upper shroud 21for movement of a horizontal spring retaining shoulder screw 57 forcedupward by the spring 51 force and moving along the slot 27 as pressureis placed on the lower shroud 41 as a leading edge thereof is movedalong a work piece. Hence, spring retaining shoulder screw 57 is coupledto the forward jaw 41. An inner slot 37 is provided to the middle jaw31; however, the inner slot 37 is smaller in length, so that whenhorizontal screw 57 travels the length of the inner slot 37 it will hitan end of said slot 37 and further move the middle jaw the rest of theway along slot 27 as shown in FIG. 9 and FIG. 10.

Also with regard to FIG. 5, FIG. 6 and further FIG. 7, a bump stop 28 iscoupled to the lower shroud 22 and limits forward motion when the device10 is fully extended by spring force 53. Tab 32 provides the extendedportion against the bump stop 28. Conversely at the retracted range ofmotion, tab 32 will hit ridge wall 23 at the fully retracted positionillustrated by FIG. 11.

FIG. 7 provides an exploded view of all components. At the forward end,an aperture 62 is provided to removably secure the scoop 63 havingangled surface 63 a for making specific cuts to a work piece. Circularcarve out 35 is configured to middle jaw 31 forward edge to fit aroundaperture 62 and any screw or bolt configured thereto. As stated, thejaws 31, 41 rotate about a pivot 33, 43, 53 that is above and rearwardof saw blade 91 center. Hence, concentric apertures 33, 43 are providedoverlapping having the spring pin 53 there through. FIG. 8 is anenlarged view of area bound by line 8 in FIG. 3, however from anopposite side since both sides are identical. As shown, spring 51 iscoupled to horizontal shoulder screw 57 further being coupled to theforward jaw 41. The view also provides closer inspection of outer 27 andinner 37 slots.

Importantly, the invention comprises in alternative embodiments, onetelescoping or two telescoping jaws, 31, 41 that are rigid and canengage a work piece at different angles 63 a via different scoops 63.Tabs 64 and mounting holes 62 are further provided at said leading edgefor mounting different scoops 63 thereto. The scoops 63 assist in makingcuts from various angles as well as various positions relative to thework piece.

Also with reference to FIG. 7, the forward jaw 41 comprises a roller 61configured horizontally at a leading edge (or lower portion of theleading edge of jaw 41). The roller 61 is configured thereto for rollingacross a workpiece while cuts are being made. As stated, the jaws 31, 41are retractable with an opposing force (typically pressing against awork piece) against helical torsion spring 51 force.

While the particular Dust Guard for Circular Saws as herein shown anddisclosed in detail is fully capable of obtaining the objects andproviding the advantages herein before stated, it is to be understoodthat it is merely illustrative of the presently preferred embodiments ofthe invention and that no limitations are intended to the details ofconstruction or design herein shown other than as described in theappended claims.

Insubstantial changes from the claimed subject matter as viewed by aperson with ordinary skill in the art, now known or later devised, areexpressly contemplated as being equivalently within the scope of theclaims. Therefore, obvious substitutions now or later known to one withordinary skill in the art are defined to be within the scope of thedefined elements.

The invention claimed is:
 1. A dust guard for providing an air flowconduit at a saw blade comprising: a telescoping jaw configured toretract into a lower shroud and rotating about a pivot point withrespect to an upper shroud and the lower shroud; and a spring directlycoupling the telescoping jaw to the upper shroud and configured suchthat a spring force holds the telescoping jaw in a fully extendedposition, wherein the spring force provides a force against thetelescoping jaw as the telescoping jaw is retracted towards a retractedposition, the spring further comprising an arm coupled to a horizontalscrew, wherein the horizontal screw is coupled to the telescoping jawand configured to slide along and within a slot in the upper shroud asthe telescoping jaw rotates with respect to the upper shroud.
 2. Thedust guard for providing an air flow conduit at a saw blade of claim 1,the telescoping jaw further comprising a middle jaw telescoping withrespect to the lower shroud.
 3. The dust guard for providing an air flowconduit at a saw blade of claim 2, the telescoping jaw furthercomprising a forward jaw telescoping with respect to the middle jaw. 4.The dust guard for providing an air flow conduit at a saw blade of claim3, the forward jaw further comprising a roller at a horizontal leadingedge of said forward jaw.
 5. The dust guard for providing an air flowconduit at a saw blade of claim 3, the forward jaw further comprising: afirst scoop having a first angled surface removably secured with respectto the forward jaw, the first scoop providing a guide for making angledcuts; and a second scoop removably secured with respect to the forwardjaw, the second scoop providing a second angled surface with respect tothe first angled surface of the first scoop.
 6. The dust guard forproviding an air flow conduit at a saw blade of claim 2, furthercomprising a ridge wall at a junction between the upper shroud and thelower shroud, the ridge wall providing a rear stop when the middle jawis fully retracted.
 7. The dust guard for providing an air flow conduitat a saw blade of claim 2, further comprising a bump stop coupled to thelower shroud, the bump stop providing a forward stop when the middle jawis fully extended.
 8. The dust guard for providing an air flow conduitat a saw blade of claim 1, further comprising a flange configuredbetween the upper shroud and the lower shroud.
 9. The dust guard forproviding an air flow conduit at a saw blade of claim 1, wherein thespring is a helical torsion spring.
 10. The dust guard for providing anair flow conduit at a saw blade of claim 9, wherein the slot is a firstslot, wherein the telescoping jaw further comprises a forward jaw and amiddle jaw, the middle jaw further comprising an inner slot configuredalongside and parallel to the first slot and having a shorter lengththan the first slot.
 11. The dust guard for providing an air flowconduit at a saw blade of claim 10, wherein the horizontal screwcontacts an end of the inner slot when the horizontal screw travels alength of the inner slot.
 12. The dust guard for providing an air flowconduit at a saw blade of claim 11, wherein the middle jaw is configuredto move a remaining distance along the first slot as the forward jaw andmiddle jaw fully retract and extend.
 13. A circular saw blade dust guardapparatus comprising: a shroud configured to form an enclosure bysurrounding portions of both sides of a saw blade to provide a conduitconfigured to suction dust and capable of holding a negative pressurewith respect to atmosphere between the shroud and a dust holding area; atelescoping jaw rotating about at least one pivot point and comprisingat least a middle jaw portion and a forward jaw portion, wherein: themiddle jaw portion is configured to retract into the shroud; the forwardjaw portion is configured to retract into the middle jaw portion; andthe forward jaw portion further comprising at least one scoop removablysecured with respect to the forward jaw portion and configured tofacilitate angled cuts, wherein the at least one scoop comprises a firstscoop that is interchangeable with a second scoop, the first scoopproviding a first angled surface, and the second scoop providing asecond angled surface different than the first angled surface; and aspring directly coupling the telescoping jaw to the shroud andconfigured such that a spring force holds the telescoping jaw in a fullyextended position, wherein the spring force provides a force against thetelescoping jaw as the telescoping jaw is retracted towards a retractedposition.
 14. The circular saw blade dust guard apparatus of claim 13,further comprising a ridge wall within the shroud providing a rear stopwhen the middle jaw is fully retracted.
 15. The circular saw blade dustguard of claim 13, the forward jaw portion further comprising a mountingmechanism configured to facilitate removably securing the at least onescoop.
 16. The circular saw blade dust guard of claim 15, wherein themounting mechanism comprises at least one tab and at least one mountinghole.